Journal of Pure and Applied Algebra Open Archive

List of the recent articles made freely available as part of this journal’s open archive. All articles published after 48 months have unrestricted access and will remain permanently free to read and download.

For a matrix coalgebra C over some field, we determine all small subcoalgebras of the free Hopf algebra on C, the free Hopf algebra with a bijective antipode on C, and the free Hopf algebra with antipode...

For an associative ring R, let P be an R-module with S=EndR(P). C. Menini and A. Orsatti posed the question of when the related functor HomR(P,−) (with left adjoint P⊗S−) induces an equivalence between...

Let Un denote the group of upper n×n unitriangular matrices over a fixed finite field F of order q. That is, Un consists of upper triangular n×n matrices having every diagonal entry equal to 1. It is...

Let S be a polynomial ring and I be the Stanley–Reisner ideal of a simplicial complex Δ. The purpose of this paper is investigating the Buchsbaum property of S/I(r) when Δ is pure dimension 1. We shall...

Let X be a smooth complex projective variety of dimension 3 and let L be an ample line bundle on X. In this paper, we provide a lower bound for h0(m(KX+L)) under the assumption that κ(KX+L)≥0. In particular,...

One of our main results is a classification of all the weakly symmetric radical cube zero finite dimensional algebras over an algebraically closed field having a theory of support via the Hochschild...

In this paper we determine the multiplicative structure of Hochschild cohomology rings of d-Koszul algebras with the Yoneda products based on an explicit construction of a chain map Δ:P→P⊗AP lifting...

Integral quadratic forms q:Zn→Z, with n≥1, and the sets Rq(d)={v∈Zn;q(v)=d}, with d∈Z, of their integral roots are studied by means of mesh translation quivers defined by Z-bilinear morsifications bA:Zn×Zn→Z...

Raikov’s conjecture states that semi-abelian categories are quasi-abelian. A first counterexample is contained in a paper of Bonet and Dierolf who considered the category of bornological locally convex...

The first major study of p-groups of maximal class was made by Blackburn in 1958. He showed that an important invariant parameter of these groups is its ‘degree of commutativity’, which is a measure...

Suppose that M is a simplicial model category and that F is a contravariant simplicial functor defined on M which takes values in pointed simplicial sets. This note displays conditions on the simplicial...

The j-multiplicity is an invariant that can be defined for any ideal in a Noetherian local ring (R,m). It is equal to the Hilbert–Samuel multiplicity if the ideal is m-primary. In this paper we explore...

The article is related with the question if representation-finite algebras form an open Z-scheme in the sense of Jensen and Lenzing (1989) [12, Chapter 12]. We define a class TMCL of algebras and we...

Let D be the ring of differential operators on a smooth irreducible affine variety X over C, or, more generally, the enveloping algebra of any locally free Lie algebroid on X. The category of finitely...

We prove that the Goodwillie tower of a weak equivalence preserving functor from spaces to spectra can be expressed in terms of the tower for stable mapping spaces. Our proof is motivated by interpreting...

This paper considers finite group actions on compact bordered surfaces — quotients of unbordered orientable surfaces under the action of a reflectional symmetry. Classification of such actions (up to...

Let H be a Krull monoid with infinite cyclic class group G and let GP⊂G denote the set of classes containing prime divisors. We study under which conditions on GP some of the main finiteness properties...

Given a strongly semistable principal bundle EG over a curve, in Biswas et al. (2006) [4], a group-scheme for it was constructed, which was named as the monodromy group-scheme. Here we extend the construction...

Let A be a noetherian commutative ring of dimension d and L be a rank one projectiveA-module. For 1≤r≤d, we define obstruction groups Er(A,L). This extends the original definition due to Nori, in the...

Let v be a henselian valuation of arbitrary rank of a field K and ṽ be the prolongation of v to the algebraic closure K˜ of K with value group G˜. In 2008, Ron Brown gave a class P of monic irreducible...

In this paper, we describe the structure of quadratic homogeneous quasi-translations, and we prove that, in dimension 9 and less, such a map is linearly triangularizable, or equivalently a quadratic...

Overlap algebras are complete lattices enriched with an extra primitive relation, called “overlap”. The new notion of overlap relation satisfies a set of axioms intended to capture, in a positive way,...

The category of modules over a string algebra is equipped with a tensor product defined point-wise and arrow-wise in terms of the underlying quiver. In the present article we investigate how this tensor...

We compute the motivic cohomology groups of the simplicial motive Xθ of a Rost variety for an n-symbol θ in Galois cohomology of a field. As an application we compute the kernel and cokernel of multiplication...

To provide a geometrical description of the classification theory and the structure theory of varieties of almost minimal degree, that is of non-degenerate irreducible projective varieties whose degree...

We introduce and investigate the ribbon groupoid associated with a Garside group. Under a technical hypothesis, we prove that this category is a Garside groupoid. We decompose this groupoid into a semi-direct...

The intersection curve between two surfaces in three-dimensional real projective space RP3 is important in the study of computer graphics and solid modelling. However, much of the past work has been...

For ∗ a star operation of finite type call a domain D a domain of finite ∗-character if every nonzero nonunit of D is contained in at most a finite number of maximal ∗-ideals. We prove a result that...